• 한국축산식품학회지
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• 제26권3호
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• pp.402-409
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• 2006

Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.

• Journal of Dairy Science and Biotechnology
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• 제33권4호
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• pp.271-275
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• 2015

Colloidal semiconductor CdSe-ZnS core-shell nanocrystal quantum dot (Qdot) are luminescent inorganic fluorophores that show potential to overcome some of the functional limitations encountered with organic dyes in fluorescence labeling applications. Salmonella Enteritidis has emerged as a major cause of human salmonellosis worldwide since the 1980s. A rapid, specific, and sensitive method for the detection of Salmonella Enteritidis was developed using Qdot as a fluorescence marker coupled with immunomagnetic separation. Magnetic beads coated with anti-Salmonella Enteritidis antibodies were employed to selectively capture the target bacteria, and biotin-conjugated anti-Salmonella antibodies were added to form sandwich immune complexes. After magnetic separation, the immune complexes were labeled with Qdot via biotin-streptavidin conjugation, and fluorescence measurement was carried out using a fluorescence measurement system. The detection limit of the Qdot method was a Salmonella Enteritidis concentration of $10^3$ colony-forming units (CFU)/mL, whereas the conventional fluorescein isothiocyanate-based method required over $10^5CFU/mL$. The total detection time was within 2 h. In addition to the potential for general nanotechnology development, these results suggest a new rapid detection method of various pathogenic bacteria from a complex food matrix.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.390-393
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• 2000

재조합 발광미생물인 UV2와 YH9을 보존제로서 trehalose를 혼합한 현탁액을 바로 동결건조한 것과 이 현탁액을 $30^{\circ}C$ incubator에서 15분 동안 진탕배양한 후 동결건조한 것과 trehalose가 첨가된 배지에 약 $6{\sim}7$시간 정도 배양한 배양액을 동결건조한 결과, trehalose를 첨가한 후 15분 동안 진탕배양했을 경우가 UV2는 0.08M의 이상에서 약 45.0%, 50.0%, YH9은 0.16M에서 48.7%, 54.1%로 회복율을 가장 높이는 최적의 조건으로 조사되었다.

• 한국잠사학회:학술대회논문집
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• 한국잠사학회 2003년도 International Symposium of Silkworm/Insect Biotechnology and Annual Meeting of Korea Society of Sericultural Science
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• pp.136-137
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• 2003

Fireflies, the luminescent insect, have species specific flash patterns, being recognized as sexual communication. The lucifrrase gene is sole enzyme responsible for bioluminescence. The firefly luciferase gene is widely used as a genetic marker or as a reporter gene in a variety of organism including bacteria, plants and animals. In this study, we illustrate the complete organization of the genomic structure of the luciferase gene from L. lateralis sampled in Boun and Muju, Korea. (omitted)

• KSBB Journal
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• 제14권1호
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• pp.91-95
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• 1999

P. phosphoreum의 고정화에 있어 중요한 것은 Matrix의 선택이며, Matrix로서 sodium algnate만을 사용하여 고정화하는 것보다는 strontnum chloride를 첨가하였을 때 세포의 bio-iummescence 유지도가 증가하였다. 저장 온도에 따른 bio-iummescence 유지도와 관련하여 -$70^{\circ}C,\;-20^{\circ}C,\;20^{\circ}C$에서 저장한 세포의 경우 저장 1일 후에 급격한 bioluminescence의 감소를 보였으나 $4^{\circ}C$ 에서 저장한 세포는 bioluminescence의 유지도가 15일 이상 이어졌다. 따라서 P. phosphoreum의 bioluminescence 안정성에 있어 가장 좋은 결과를 나타낸 것은 2.5%(W/W)sodium alginate와 0.3M(W/V)strontnum chloride 를 사용하여 고정화한 세포였으며 저장 온도는 $4^{\circ}C$였다.

• Journal of Microbiology
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• 제38권3호
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• pp.150-155
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• 2000

A bioluminescent assay method for detecting the activity of phospholipase C(PLC; phosphatidyl choline cholinephosphohydrolase, EC 3.1.4.3) was developed using bioluminescent marine bacteria. Phospholipase C from Bacillus cereus and sn-1,2- dimyristoyl glycerol was further hydrolyzed with lipase from Candida ecylidracea. The hydrolyzed myristic acid was quantified using a dark mutant of Vibrio harveyi (designated as M-17). The in vivo light intensity of which was stimulated specifically up to one thousand fold in the presence of myristic acid. The rates of the hdrolysis of the DMPC substrate by the phospholipase measured by the luminescence method were linear with time and the were estalished to detect as little as 0.1 mUnit of phospholipase C and 5 nM of myristic acid production.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.349-353
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• 2002

Two recombinant bacteria containing luxAB showed an increased tolerance to stresses associated with lyophilization, when the cells were freeze-dried in the presence of trehalose. In the case of a recombinant, UV2, only $2.5\%$ of the original bioluminescence and $2.7\%$ of the cell viability were restored after 4 h of freeze-drying without trehalose, which implies that the cells were heavily damaged during the dehydration. To improve these losses, trehalose was added before freeze-drying using different modes. Trehalose increased the bioluminescence and the viability of freeze-dried UV2 under all conditions tested, and it was also observed that the addition of trehalose to the cultures (final concentration of 0.08 M) for 15 min before the freeze-drying resulted in the restoration of $45\%$ of the original bioluminescence and $50\%$ of the cell viability. Trehalose also showed a similar efficacy with the other luminescent recombinant, YH9. Therefore, it was tentatively concluded that trehalose played a role as a protective agent in the freeze-drying of bacterial cells.

• 환경영향평가
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• 제32권2호
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• pp.123-133
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• 2023

이차전지 생산공정에서 발생한 폐수에는 리튬과 고농도의 황산염을 포함하고 있으며 최근에는 에너지 밀도가 높은 High Ni 계열의 전구체 수요가 급증하면서 니켈의 배출도 우려되는 상황이다. 리튬과 황산염의 경우 현재 수질오염물질 배출허용기준에 포함되어 있지 않으므로, 이들이 적절하게 처리되지 못하고 배출되었을 경우 향후 환경에 대한 부정적 영향이 클 수 있을 것으로 예상된다. 따라서 본 연구에서는 물벼룩(Daphnia magna)과 발광박테리아(Aliivibrio fischeri)를 이용하여 이차전지 생산공정 배출수에 포함되어 배출될 수 있는 잠재오염물질인 리튬과 니켈 및 황산염의 생태독성을 평가하였다. 생태독성평가 결과, 물벼룩 24시간, 48시간 리튬 EC₅₀ 값은 18.2mg/L, 14.5mg/L, 니켈의 경우 7.2mg/L와 5.4mg/L, 황산염 EC₅₀ 값은 4,605.5mg/L, 4,345.0mg/L로 나타나, 물벼룩의 경우 물질 및 반응시간(24시간, 48시간)에 따른 생태독성 차이가 있음을 알 수 있었다. 리튬, 니켈, 황산염에 대한 물벼룩의 EC₅₀을 비교하면, 니켈의 24h 및 48h EC₅₀은 리튬에 비해 39.6-37.2%, 황산염에 비해서는 0.1-0.2% 수준으로 세 물질 중 가장 독성이 강한 것으로 나타났다. 그 차이는 노출시간과 상관없이 유사한 수준으로 나타났다. 반면, 황산염의 EC₅₀은 리튬과 니켈에 비해 각각 253.0-299.7%, 639.5-804.6% 수준으로 세물질 중 독성이 가장 약한 것으로 나타났다. 발광박테리아의 리튬에 대한 30분 EC₅₀ 값은 2,755.8mg/L, 니켈은 7.4mg/L, 황산염 EC₅₀ 값은 66,047.3mg/L로 니켈과는 달리 리튬과 황산염에 대한 물벼룩과 발광박테리아 생물 종별 민감도 차이도 있음을 확인하였다. 이차전지 배출수 관리를 위해 향후 이들 물질에 대한 복합 독성에 관한 연구가 필요할 것으로 판단된다.

• Nuclear Medicine and Molecular Imaging
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• 제43권4호
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• pp.344-351
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• 2009

목적: 광학영상기술은 소동물이나 임상연구에서 분자영상법으로 알려진 첨단연구 분야이다. 광학영상기기는 소동물영상연구 및 추적연구에 중요한 역할을 수행하고 있다. 발광영상에서 소동물을 영상화 하기 위해서는 피부조직을 뚫고 나오는 광자를 검출하기 위한 고민감도 CCD카메라가 필요하다. 이 연구에서는 소동물에서 발생하는 발광신호를 검출하기 위해 개발한 광학영상기기를 소개하고자 한다. 대상 및 방법: 냉각형 CCD카메라와 집광렌즈, 8개의 백색광 LED광원을 암실상자 안에 장치하였다. 팬텀 및 튜브를 이용한 영상을 얻은 후 발광 박테리아를 이용하여 CT26 암모델 누드마우스에서 영상을 획득하였다. 결과: 발광영상을 얻기 위한 광학영상기기를 설계하고 개발하였다. 영상획득이 성공적으로 수행되었고, 시스템을 완성하였다. 개발된 장비는 분자영상연구에 사용되고 있다. 결론 개발된 광학영상장비는 다양한 실험적 조건을 만족하는 연구에 최적화하여 유용한 도구로 자리잡을 것으로 기대한다.

• ALGAE
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• 제18권2호
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• pp.157-167
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• 2003

Effect of the effluent of the sewage and wastewater plants on the algal growth was investigated from the 19 plants located in the Nakdong river basin. Most of the samples showed high values of the algal growth potential (AGP) when they were mixed with natural river water at 20% of final concentration. At 20% of the mixing ratio, the mixed effluents of sewage and wastewater showed 3.5 and 1.8 times higher AGP than those of the natural river water. The higher AGP values are attributable to the high contents of phosphorus and ammonium in the effluent. The mixing ratio of effluents of the discharge/river flow was highest in the Kumho River (42.8%) followed by the middle of Nakdong River (22.7%), Kam Stream (13.9%), Byungsung Stream (13.3%), Yangsan Stream (7.9%), and Young River (5.4%). Comparison of the trophic state of the effluents with natural river water indicated that the effluents showed higher trophic values than natural water. Concentrations of total phosphorus, total nitrogen and conductivity in the effluents were 12.3, 4.9 and 5.3 times higher than the those found in natural river water respectively. The AGP values were highly related with the trophicity of the water especially on the concentrations of phosphate and ammonium. Toxicities of the treated sewage water, wastewater and livestock waste water tested by the luminescent bacteria, Vibrio fischerii were generally low.